Carburizing process



Jan. 28, 1930. A. w. MACHLET CARBURIZING PROCESS Filed May 6, 1927 become carburized, the gas used being a hy- Patented Jan. 28, 1930- UNITE STATES ADOLIPH W. MACHLET, OE

Application filed May 6, 1927. Serial No. 189,281.

'This invention relates to carburizing of iron, steel and other articles.

As set forth inPatent No. 1,337, 244, carburizing gasis caused to flow through a heated retort, whereby articles in the retort and sold in flasks at a'pressure of 110 pounds or more per s uare inch. This liquid, upon being released, expands into the form of gas, which it is desired to use in carburizing.

volving the present invention. a

The object of the present invention is to, make it practicable to carburize with such gases which have proven to be prohibitively carbonous or lampblack-depositlng. v

Other features and advantages will hereinafter appear.

The accompanying drawing or diagram indicates an apparatus or organization 111-,

In carrying out this invention, the preparation of propane is released from a tube 10, and may expand into a bell or gasometer in which it may remain undersome pressure. There may also be umped into the bell a.

- 7 volume of air ata li e pressure; there being about three or four times as much volume of air as of propane. This gas is not apt to explodew'hen the volume of the gas is more than one-tenth of the volume of air.

Instead of a bell, there is preferably use a gas-and-air mixerll, having at 12 a duct or communication for inflow of gas from tube 10 to the mixer, said duct having a pressure gage 13 and a'pressure-reducing or controlling valve 14. These mixers are usually provided with adjustable means (not shown\ CARBURIZING PROCESS gas' from the retort.

PATENT OFFICE I REISSTUED for regulating the proportions of volumes of the gases forming the delivered mixture.

For mixing the air and gas in any desired proportions, there may be used the wellknown Schematische Darstellungeines Selas- Apparates. Air is drawn into the mixer through an-inlet 14. A pump 15, driven by a'belt pulley 16, draws the mixture from the mixer 11, and may be provided with the automatic by-pass device '17 which is usual in air or gas pumps, to permit the'mixture to flow idly back from the delivery end 18 to the intake end 19 of the pump, when the pump is delivering the mixed gas and air faster than is required, or when communication between the pump and carburizer is closed.

From the pump a flexible hose 20 conducts the mixture to a pipe21 having a. valve 22 to control the supply of carburizing gas to the carburizing retort 23, whichis heated in a furnace 24. There may be a lifting and falling movement of the retort, in loading and discharging articles from the same, this movement being accommodated by the flexible supply pipe 20. The revolving retorttis sealed by a cover 25 hooked onto the delivery end of the retort. The cover is provided.

with a vent 26 for slow escape of viti'ated The retort and furnace may be constructed in the manner disclosed in said United States Patent No. 1,337,244,

grantedto me April 20, 1920.

The mixed propane and air, delivered from the hell or gasometer, or fromthe mixer 11, to the retort 23 of the carburizin apparatus,

ives excellent carburizing res ts upon the iron or steel articles in the retort, with little or no deposit of lampblack upon the carburized articles. This renders propane practicable for use in carburizing, and gives a wide outlet for'this class of manufacture, and fills a long-felt want in the art, especially-where city gas or other gas is not at hand for car burizing purposes. Moreover, owing to the small proportion or volume of propane 1n the described carburizing mixture, the expen se of using propane is so far reduced that it can be used successfully in competition with i city'gas, and-With other cheap grades commonly used for carburizing.

If a gasometer is used, it will be understood that air can be forced into the gasometer by a pump Having suitable pressure indicators, and that there may also be provided for the pump a relief valve or bypass, so that the ressure of the gas in the gasometer will not come excessive, even though the pump is kept running. When a gasometer is used, any suitable means may be provided for proportioning the mixture of air and propane' The im rovements may also be used with some gra es of city gas, natural gas, oil gas, etc.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, 1 claim: v

1. The carburizing process consisting in compressing propane gas to liquid form, permitting expansion of the liquid to gas form, reducing the expanded gas by adding thereto about three volumes of atmospheric air to one volume of the expanded gas, and carburizing ironor steel articles by heating them w in an atmosphere of the gas so reduced, thereby substantially avoiding the faulty deposit of lampblack upon the articles.

2. The carburizing process consisting in compressing propane gas to liquid form, permitting expansion of the liquid to form gas to 'a certain pressure above atmospheric, re-

ducing the expanded gas while under pressure by the forcible addition thereto of about three volumes of atmospheric air to one volume of the expanded gas, and carburizing iron or steel articles by heating them in anatmosphere ofthe reduced gas under pressure above atmospheric.

ADOLPH w. MACI-MILET. 

